Genome-wide analysis of gene expression and intron retention during deveopment in a U12-type splicing-deficient zebrafish mutant [microarray]
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ABSTRACT: To determine the global impact of the clbn mutation on gene expression and efficiency of U2- and U12-type splicing, we analyzed the transcriptome of 108hpf wt and clbn mutant larvae by microarrays and RNA sequencing. RNAseq data was used to characterize intron retention of U2-type and U12-type intron on a genome-wide scale to confirm that rnpc3 deficiency specifically impairs U12-type splicing. RNAseq and microarray data were combined to yield high-confidence lists of differentially expressed genes which show that impaired U12-type splicing has a wide-ranging effect on the developing transcriptome. Total RNA was prepared from pools consisting of approx. 20 individually genotyped homozygous wildtype or mutant larvae, respectively. Three biologically independent replicate pools were generated and analyzed for each condition.
Project description:To determine the global impact of the clbn mutation on gene expression and efficiency of U2- and U12-type splicing, we analyzed the transcriptome of 108hpf wt and clbn mutant larvae by microarrays and RNA sequencing. RNAseq data was used to characterize intron retention of U2-type and U12-type intron on a genome-wide scale to confirm that rnpc3 deficiency specifically impairs U12-type splicing. RNAseq and microarray data were combined to yield high-confidence lists of differentially expressed genes which show that impaired U12-type splicing has a wide-ranging effect on the developing transcriptome. RNAseq libraries prepared from 108 hours post-fertilization zebrafish larvae (approx. 60 embryos each, genotyped homozygous wildtype and homozygous clbns841 mutants, respectively)
Project description:To determine the global impact of the clbn mutation on gene expression and efficiency of U2- and U12-type splicing, we analyzed the transcriptome of 108hpf wt and clbn mutant larvae by microarrays and RNA sequencing. RNAseq data was used to characterize intron retention of U2-type and U12-type intron on a genome-wide scale to confirm that rnpc3 deficiency specifically impairs U12-type splicing. RNAseq and microarray data were combined to yield high-confidence lists of differentially expressed genes which show that impaired U12-type splicing has a wide-ranging effect on the developing transcriptome.
Project description:To determine the global impact of the clbn mutation on gene expression and efficiency of U2- and U12-type splicing, we analyzed the transcriptome of 108hpf wt and clbn mutant larvae by microarrays and RNA sequencing. RNAseq data was used to characterize intron retention of U2-type and U12-type intron on a genome-wide scale to confirm that rnpc3 deficiency specifically impairs U12-type splicing. RNAseq and microarray data were combined to yield high-confidence lists of differentially expressed genes which show that impaired U12-type splicing has a wide-ranging effect on the developing transcriptome.
Project description:Eukaryotic nuclear introns have been dichotomously classified into common U2-type introns and rare U12-type introns. Because the highly conserved consensus sequences for the 5’ splice site and the branch point are found within all U12-type introns, weighted matrices for these motifs are used for prediction of U12-type introns. However, the U12-type consensus sequences per se are also recognized by the U2-type spliceosome. To better understand how distinct splicing systems recognize their authentic splice sites, we determined the binding sites of splicing factors, U2AF1 and ZRSR2, and found that ZRSR2 binding is mostly limited to U12-type introns. Our results reveal RNA elements contributing to selection of U2-type and U12-type splice sites in a mutually exclusive manner.
Project description:U12-type or minor (U12) introns are spliced by a distinct minor spliceosome and are found in the vast majority of multicellular eukaryotes, including plants and animals. Although U12 introns constitute less than 0.5% of all introns in many species, minor intron containing genes (MIGs) are important for organismal growth, development and pathology. We recently reported that maize RNA Binding Motif Protein 48 (RBM48) is required for U12-type intron splicing. Maize rbm48 mutants have genome-wide defects of U12 intron splicing, leading to abnormal endosperm cell differentiation and proliferation. To investigate whether RBM48 mediated U12 splicing is conserved between maize and humans, we generated a CRISPR/Cas9-mediated RBM48 functional knockout of the human RBM48 ortholog (RBM48 FunKO) in human K-562 cells.
Project description:SF3B1 is one of shared components of U2 and U12 snRNPs that are required for splicing of U2-type and U12-type introns, respectively. Interestingly, recurrent somatic mutations have been identified in the spliceosome components in human cancer. By using CLIP-seq for SF3B1, binding sites in human embryonic stem cells were determined. The most prominent binidng sites were at 3' splice sites on pre-mRNA. Interestingly, 5' and 3' ends of introns spliced out were enriched by CLIP.
Project description:U12-type introns were originally recognized based on their highly conserved non-consensus AT-AC termini1,2, which are spliced by a separate minor spliceosome3,4. Padgett and Krainer groups later showed that terminal dinucleotides do not differentiate U12-type from U2-type introns, as there are U12-type introns with GT-AG termini and U2-type introns with AT-AC termini5,6. Rather, U12-type introns are recognized by their divergent and highly conserved 5’ splice site (5’ss) and branch point sequences, which both differ from the consensus sequences found in U2-type introns. To date, no functional differences have been ascribed to AT-AC or GT-AG subtypes of U12-type introns, nor have RNAseq analyses of minor spliceosome diseases reported any subtype specificity. Here, we describe a novel protein component of the minor spliceosome, encoded by the CENATAC locus, that is required for accurate splicing of AT-AC but not GT-AG type minor introns. CENATAC was initially identified in a subset of Mosaic Variegated Aneuploidy (MVA) patients with mutations in CENATAC, which lead to chromosome congression defects during mitosis. Earlier large-scale proteomic analyses tentatively classified CENATAC as a spliceosome component and phylogenetic analyses showed co-segregation of CENATAC with minor spliceosome components. Targeted depletion of CENATAC in HeLa cells, followed by RNAseq revealed global retention of AT-AC minor subtype introns with more than 60% showing statistically significant (up to 90%) intron retention (IR). Additionally, U12-type introns with 5’-AT, but divergent 3’-terminal dinucleotides also showed significant IR. We also detected cryptic U2-type splice site activation near affected AT-AC introns. In contrast, about 10% of GT-AG subtype introns responded to CENATAC depletion. Co-IP experiments revealed that CENATAC is not a U11/U12 di-snRNP component as expected for a specificity factor, but rather associates with the U4atac/U6atac.U5 tri-snRNP via interaction with PRPF3/4, suggesting a role for minor tri-snRNP in initial 5’ss recognition. CENATAC also interacts with TXNL4B, a paralog of TXNL4A in the major tri-snRNP. Finally, several genes encoding chromosome congression factors harbor U12 AT-AC-type introns that were highly retained in CENATAC depleted cells, potentially explaining the aneuploidy phenotype observed in MVA patients.
Project description:Somatic mutations in the spliceosome gene ZRSR2 (located on the X chromosome) are associated with myelodysplastic syndrome (MDS). ZRSR2 is involved in the recognition of 3' splice site during the early stages of spliceosome assembly; however, its precise role in RNA splicing has remained unclear. Here, we characterize ZRSR2 as an essential component of the minor spliceosome (U12-dependent) assembly. shRNA mediated knockdown of ZRSR2 leads to impaired splicing of the U12-type introns, and RNA-Sequencing of MDS bone marrow reveals that loss of ZRSR2 activity causes increased mis-splicing. These splicing defects involve retention of the U12-type introns while splicing of the U2-type introns remain mostly unaffected. ZRSR2 deficient cells also exhibit reduced proliferation potential and distinct alterations in myeloid and erythroid differentiation in vitro. These data identify a specific role for ZRSR2 in RNA splicing and highlight dysregulated splicing of U12-type introns as a characteristic feature of ZRSR2 mutations in MDS. RNA sequencing was performed on 16 bone marrow samples (MDS and normal) and six samples of control or ZRSR2 shRNA transduced TF-1 cells and data was analysed for aberrant splicing caused by ZRSR2 mutations/deficiency.
Project description:The maize Rough endosperm3 (Rgh3) gene encodes an ortholog of the human essential splicing factor, ZRSR2. To test whether a mutation in Rgh3 affects mRNA splicing, we compared rgh3 mutants and wild-type sibling transcriptomes in an RNA-seq experiment. Twelve libraries were constructed with mRNA extracted from the roots and shoots of three seedlings of each genotype. The libraries were multiplexed and sequenced on one lane of the HiSeq 2000 platform. The run produced 149 million paired-end 100 bp reads that mapped to 35,028 genes. Two approaches were used to analyze the dataset. In the first approach, Mosaik2, FreeBayes, GSNAP, and Cufflinks were used to identify differences in transcript isoform abundance in a SNP-tolerant fashion. During reverse-transcription PCR validation, six examples of intron retention were found to occur more frequently in rgh3 seedlings, and all six introns were members of a rare class of introns called U12-type introns. The second approach utilized a t-test to determine whether more reads were mapped to U12-type introns in rgh3 libraries relative to wild-type libraries. Out of all U12-type introns within genes that are expressed at a early seedling stage, 43% exhibit splicing defects in rgh3 mutants. These U12-type intron splicing defects include intron retention and cryptic splice site activation. We report that the rgh3 mutation specifically impairs the U12-type intron splicing.
Project description:A Drosophila line (l(2)k01105) with a P-element insertion in U6atac snRNA, an essential component of the U12-type spliceosome, was used to investigate the impact of disrupted U12-dependent splicing during larval development. A custom-designed exon array was used to study the expression of genes containing U12-type introns and genes involved in downstream pathways affected by deficient U12-dependent splicing. Flies homozygous for the U6atac mutation (U6atac/U6atac) were compared to heterozygotes (U6atac/CyO-GFP) which have a normal phenotype. Samples from homozygous and heterozygous U6atac mutant larvae at 1st, 2nd and 3rd larval instar were labelled with three colours and hybridized three samples per array. Three independently harvested biological replicates were made, with dye swap, except only two replicates for 3rd stage heterozygous control. This study presents exon-level data. Supplementary files: Raw data (.gpr) files. Series variables and repeats information.